$ npm install p-reflect
p-reflect
Make a promise always fulfill with its actual fulfillment value or rejection reason
Useful when you want a promise to fulfill no matter what and would rather handle the actual state afterwards.
Install
$ npm install p-reflect
Usage
Here, Promise.all would normally fail early because one of the promises rejects, but by using p-reflect, we can ignore the rejection and handle it later on.
import pReflect from 'p-reflect';
const promises = [
getPromise(),
getPromiseThatRejects(),
getPromise()
];
const results = await Promise.all(promises.map(pReflect));
console.log(results);
/*
[
{
status: 'fulfilled',
value: '🦄'
isFulfilled: true,
isRejected: false
},
{
status: 'rejected',
reason: [Error: 👹]
isFulfilled: false,
isRejected: true
},
{
status: 'fulfilled',
value: '🐴'
isFulfilled: true,
isRejected: false
}
]
*/
const resolvedString = results
.filter(result => result.isFulfilled)
.map(result => result.value)
.join('');
console.log(resolvedString);
//=> '🦄🐴'
The above is just an example. Use p-settle if you need exactly that.
API
pReflect(promise)
Returns a Promise<Object>.
The object has the following properties:
status('fulfilled'or'rejected', depending on how the promise resolved)valueorreason(Depending on whether the promise fulfilled or rejected)isFulfilledisRejected
promise
Type: Promise
A promise to reflect upon.
isFulfilled(object)
This is a type guard for TypeScript users.
Returns true if the object has the property value, false otherwise.
This is useful since await pReflect(promise) always returns a PromiseResult. This function can be used to determine whether PromiseResult is PromiseFulfilledResult or PromiseRejectedResult.
This is a workaround for microsoft/TypeScript#32399
- reference documentation Using type predicates
isRejected(object)
This is a type guard for TypeScript users.
Returns true if the object has the property reason, false otherwise.
This is useful since await pReflect(promise) always returns a PromiseResult. This function can be used to determine whether PromiseResult is PromiseRejectedResult or PromiseFulfilledResult.
Related
Current Tags
- 3.1.0 ... latest (2 years ago)
sindresorhus